CARSON, Calif. -- Marcelo Sarvas scored in the 52nd minute, and the L.A. Galaxy opened the Western Conference championship with a 1-0 victory over the Seattle Sounders on Sunday.

Jaime Penedo posted his third straight shutout for the Galaxy, who still haven't conceded a playoff goal this season.

Landon Donovan, Robbie Keane and the Galaxy also haven't lost at home since their season opener in March, and they kept the Supporters' Shield-winning Sounders off the scoresheet in a tense, chippy match.

The clubs play their second leg Nov. 30 on Seattle's artificial turf. The Galaxy could advance with a variety of results, since the tiebreaker is away goals.

The winner hosts the MLS Cup on Dec. 7.